“Here you had an INLA man hired by the Kinahans as a ‘spotter’ to help two hitmen take out a New IRA man.”

The other two men in the gardai’s sights are both from the inner city and are known criminals.

A source said: “They’re perfect for the Kinahans. They are from the area, know the layout, know the movements of the Hutches.

“Plus they don’t have to travel from the southside of the city or from Northern Ireland and risk getting caught with a firearm at a Garda checkpoint.”

The emergence of the INLA is not the first dissident group to raise its head in this bloody battle.

The Monk had already met with members of a breakaway group styling itself as the New IRA.

Gerry 'The Monk' Hutch

One of the men involved in the attack on the Kinahans at the Regency Hotel in February is a killer from Co Tyrone. He has been nicknamed “Flat Cap” as he was seen running, gun in hand and wearing a hat, from the hotel after David Byrne, 33, was shot dead.

Murder victim Barr was also from Co Tyrone.

Meanwhile, a 29-year-old man is still being questioned by gardai at Mountjoy Garda station after he gave himself up on Tuesday evening.

He is being detained under anti-gang legislation and can be held for up to a week.